Hotel California Chord Help

This is a 3.33 minute video response from Matt Brown on Nov 1st, 2008

Question:

"Kylehumer asks, "In hotel california for example you use 2 barre chords that are same name( F#) but different shapes n different sounds....how do you know from just the name which one to use and when? when do you know which string make the barre chords name? for example the bm root note and name of the barre chord is on a B, string 6 vs a F# has which is named from that root being on the 5th string""